linux-kernel - Re: [v2 PATCH] usb: gadget: bdc: use readl_poll

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Message-ID: <b73d8a90-96cd-42b5-bbc2-26e300da0603@gmail.com>
Date:   Sun, 12 Jul 2020 20:53:04 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Felipe Balbi <balbi@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        YueHaibing <yuehaibing@...wei.com>,
        Stephen Boyd <swboyd@...omium.org>, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [v2 PATCH] usb: gadget: bdc: use readl_poll_timeout() to simplify
 code



On 7/12/2020 8:30 PM, Chunfeng Yun wrote:
> Use readl_poll_timeout() to poll register status
> 
> Cc: Florian Fainelli <f.fainelli@...il.com>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
> ---
> v2 changes, suggested by Stephen:
>   1. use unsigned int instead of int for @usec parameter
>   2. add dev_log() back
>   3. drop "Err" in error log
> ---
>  drivers/usb/gadget/udc/bdc/bdc_core.c | 26 +++++++++++---------------
>  1 file changed, 11 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/bdc/bdc_core.c b/drivers/usb/gadget/udc/bdc/bdc_core.c
> index 02a3a77..53dccb1 100644
> --- a/drivers/usb/gadget/udc/bdc/bdc_core.c
> +++ b/drivers/usb/gadget/udc/bdc/bdc_core.c
> @@ -12,6 +12,7 @@
>  #include <linux/spinlock.h>
>  #include <linux/platform_device.h>
>  #include <linux/interrupt.h>
> +#include <linux/iopoll.h>
>  #include <linux/ioport.h>
>  #include <linux/io.h>
>  #include <linux/list.h>
> @@ -29,24 +30,19 @@
>  #include "bdc_dbg.h"
>  
>  /* Poll till controller status is not OIP */
> -static int poll_oip(struct bdc *bdc, int usec)
> +static int poll_oip(struct bdc *bdc, u32 usec)
>  {
>  	u32 status;
> -	/* Poll till STS!= OIP */
> -	while (usec) {
> -		status = bdc_readl(bdc->regs, BDC_BDCSC);
> -		if (BDC_CSTS(status) != BDC_OIP) {
> -			dev_dbg(bdc->dev,
> -				"poll_oip complete status=%d",
> -				BDC_CSTS(status));
> -			return 0;
> -		}
> -		udelay(10);
> -		usec -= 10;
> -	}
> -	dev_err(bdc->dev, "Err: operation timedout BDCSC: 0x%08x\n", status);
> +	int ret;
>  
> -	return -ETIMEDOUT;
> +	ret = readl_poll_timeout(bdc->regs + BDC_BDCSC, status,
> +		(BDC_CSTS(status) != BDC_OIP), 10, usec);

You could probably indent this to the opening parenthesis, but with or
without it:

Reviewed-by: Florian Fainelli <f.fainelli@...il.com>

and thanks for picking up the MAINTAINERS file update ;)

> +	if (ret)
> +		dev_err(bdc->dev, "operation timedout BDCSC: 0x%08x\n", status);
> +	else
> +		dev_dbg(bdc->dev, "%s complete status=%d", __func__, BDC_CSTS(status));
> +
> +	return ret;
>  }
>  
>  /* Stop the BDC controller */
> 

-- 
Florian